Was Ancient Florida Lush Or Arid? Soil Core May Tell

Did the inhabitants of those ancient times live in a land much as it is today, a vibrant and fertile place of life and abundance?

Or was it their lot to grub day by day in a dry and grassy plain, a melancholy and tropical Kansas of sorts?

Many of the answers to those questions await discovery in a remote spring at North Port near Charlotte Harbor in southwest Florida.

In this natural time capsule has been found the earliest evidence of human activity in the Southeastern United States -- a society that lived 120 centuries ago in what was then the center of the state.

Scientists first excavated the spring 10 years ago and concluded that it was an oasis in a grassy plain, though other evidence suggests Florida was much as it is today.

But large-scale exploration of the site has been impractical because it is so expensive, said Dr. John Gifford, University of Miami anthropology professor and one of the excavators.

Now, they want to go back.

Gifford and other university researchers have asked the National Science Foundation for a grant to underwrite the next phase of exploration.

If the request is approved, the researchers will try to take a 40-foot core from the bottom of the spring 220 feet deep. No core has ever been taken from an inland lake deeper than 100 feet.

From a floating platform, a paper-thin aluminum pipe will be

lowered to the bottom, where it will be gently vibrated into the pit's floor so as little sediment as possible will be disturbed.

''We will very carefully sample the individual layers that make up the core,'' Gifford said. ''Each layer represents a period in the

past when the sediments were deposited.''

The layers will be dated, and what the researchers find in the samples will tell them a great deal about the environment at the time. That should do much to resolve the debate over what ancient Florida was like.

It would take 18 months to analyze the core, and the findings would serve as the basis for a request for National Science Foundation funds to resume the explorations.

Then, excavations probably would be resumed on a ledge 85 feet below the surface and in a shallow part of the spring basin.

Gifford will discuss the project in a talk Oct. 29 in Orlando at a meeting of the Geological Society of America.

The site is called Little Salt Spring. It was at first thought to be just another shallow pond, but one day divers found a deep underlying sinkhole with two rock ledges, 59 and 85 feet deep. The ledges represent shorelines during periods of lower sea levels.

Another researcher, University of Miami geologist Carl Clausen, said the work ahead should provide new insights ''into the subsistence of these early people and the environment in which they lived.''

It was on the lower ledge that the earliest evidence of human activity was found -- an overturned shell of an extinct species of giant land tortoise.

A sharply pointed stake, dated by radiocarbon at 12,036 years old, had been driven into the animal. It had been cooked upside down in its shell.

Also found on the ledge were the remains of three extinct turtle species, an extinct sloth, an immature mammoth and an extinct bison.

By the period of 10,000 years ago, the water had risen to about 40 feet below today's level. During that period, Paleo-Indians lived around the sinkhole, mainly eating white-tailed deer cooked in sand hearths.

Clausen said in an article in the journal Science that the most important Paleo-Indian artifact recovered was part of an oak boomerang similar to weapons found in Australia. He said it may be the oldest specimen of its type in the world and was the first found in the Western Hemisphere.

The water level in the spring continued to rise rapidly until about 8,500 years ago. Fresh water became more available in the region and the Paleo- Indian need to remain at the site was gone.

Between 8,500 and 8,000 years ago the water level in the area began to drop, reducing supplies and making Little Salt Spring again attractive. It became the center of activity of the Archaic Period people. They left a cemetery of more than 1,000 bodies.